Page 1730 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 124: Toxicology in Adults 1199

TABLE 124-7 Common Toxidromes (Continued) TABLE 124-8 Selected Drugs Causing a Depressed Physiologic State
Toxidrome Features Drugs Drug Treatment Sympatholytics
Slurred speech Barbiturates Urinary alkalinization for Adrenergic blockers
phenobarbital Antiarrhythmics
Apnea Benzodiazepines Antihypertensives
Ethanol Antipsychotics
Meprobamate Cyclic antidepressants
Opiates Cholinergics
Hallucinogenic Hallucinations Amphetamines Benzodiazepines Bethanechol
Psychosis Cannabinoids Haloperidol Carbamates
Panic Cocaine Nicotine
Fever Lysergic acid Organophosphates
diethylamide (LSD)
Physostigmine
Mydriasis Phencyclidine (PCP)
Pilocarpine
Hyperthermia (may present with Sedative-hypnotics
miosis)
Alcohols
Extrapyramidal Rigidity/tremor Haloperidol Diphenhydramine
Barbiturates
Opisthotonos Phenothiazines Benztropine
Benzodiazepines
Trismus
Ethchlorvynol
Hyperreflexia
Narcotics
Choreoathetosis
Analgesics
Narcotic Altered mental Dextromethorphan Naloxone
status Antidiarrheal agents
Slow respirations Opioids Other
Miosis Pentazocine Carbon monoxide
Bradycardia Propoxyphene Cyanide
Hypotension Hydrogen sulfide
Hypothermia Hypoglycemic agents
Decreased bowel Lithium
sounds Salicylates
Serotonin Irritability Fluoxetine Benzodiazepine
Hyperreflexia Meperidine
Pupil reactivity and nystagmus are additional useful signs. In
Flushing Paroxetine
anticholinergic intoxication, pupils dilate and generally do not react to
Diarrhea Sertraline light, whereas in cocaine intoxication, dilated pupils usually respond
Diaphoresis Trazodone to light. Alcohols, cholinergics, lithium, carbamazepine, phenytoin, and
barbiturates cause horizontal gaze nystagmus. Phencyclidine, phenytoin,
Fever
and barbiturates cause horizontal, vertical, or rotatory nystagmus.
Trismus Selected drugs and toxins affecting muscle tone and movement
25
Tremor are listed in Table 124-12. Dystonic reactions characterized by
torticollis, tongue movements, and trismus are classic in haloperidol,
Myoclonus
phenothiazine, or metoclopramide overdose. Dyskinesias (eg, myoclo-
nus, hyperkinetic activity, and repetitive activity) are seen with anticho-
When initial signs and symptoms are less specific, we find it is useful linergics, PCP, and cocaine. Muscle rigidity with hyperthermia is the
to categorize patients as physiologically depressed (Table 124-8), or agi- characteristic of neuroleptic malignant syndrome, malignant hyperther-
tated and hyperadrenergic (Table 124-9). This categorization narrows mia, PCP intoxication, and black widow spider bite.
the list of possible ingestions and impacts initial treatment strategies ■
(see below). When confusion or delirium dominate, drugs listed in LABORATORY EVALUATION
Table 124-10 deserve consideration. Note that certain drugs, such as Clinical laboratory data include assessment of the “three gaps of toxicology”:
28
anticholinergics, present variably with stupor, coma, agitation, confu- the anion gap, the osmol gap, and the arterial oxygen saturation gap.
sion, or delirium, depending on the timing, dose, and host factors. Unexplained widening of these gaps should raise the possibility of drug
Drugs affecting the autonomic nervous system (Table 124-11) alter overdose or toxic ingestion.
pupil size. Combining the patient’s physiologic state (ie, agitated or
depressed) with pupil size provides for rapid assessment of the dominant Anion Gap: The anion gap (AG) refers to the difference between one mea-
+
−
–
ingestion. For example, the constellation of agitation, tachycardia, and sured cation (Na ) and two measured anions (mainly Cl and HCO ):
3
rotator nystagmus is suspicious for phencyclidine intoxication; lethargy, AG = [Na ] − [Cl ] − [HCO ]
−
−
+
pinpoint pupils, and slow and deep respirations are characteristic of 3
opioid overdose. 28,29 with a normal value of approximately 12 ± 4 mEq/L. 30

section11.indd 1199 1/19/2015 10:51:56 AM